A user equipment (UE) includes a processor configured to execute computer-executable instructions to: determine whether a required network slice/service of the UE is supported by a network node; perform at least one of a plurality of mobility management procedures, when the required network slice/service of the UE is not supported by the network node; where the plurality of mobility management procedures includes: selecting another master node (MN), or intra-MN handover or inter-MN handover to another MN; selecting or reselecting a secondary node (SN), intra-SN handover to another SN, modifying an existing SN, or adding a new SN; changing the UE's anchor node to a target new radio (NR) next generation node B (gNB) or a target evolved long term evolution (eLTE) evolved node B (eNB).